TITLE: Heat-curable resin composition containing acrylic polymer having
alicyclic epoxide functions
United States Patent 5326827
ABSTRACT:
A curable resin composition comprising (a) an acrylic polymer having a
plurality of alicyclic epoxide functions, and (b) an amount effective
to initiate the curing reaction of the acrylic polymer (a) upon heating
of a heat-latent cation polymerization initiator. The composition finds
its uses in coating compositions, sealants, potting and casting
compositions.
INVENTORS:
Aoki, Kei (Ikoma, JP)
Nakano, Shinji (Takatsuki, JP)
Tomita, Nobuaki (Nara, JP)
APPLICATION NUMBER: 08/139076
PUBLICATION DATE: 07/05/1994
FILING DATE: 10/21/1993
ASSIGNEE: Nippon Paint Co., Ltd. (Osaka, JP)
PRIMARY CLASS: 525/337
OTHER CLASSES: 525/327.3, 525/340, 525/341, 525/344, 525/351, 525/353, 525/355,
525/358, 525/359.1
INTERNATIONAL CLASSES: C08K5/36; C08F8/00; C08F20/32; C08G59/32; C08G59/68; C08K5/55;
C08K5/59; C08L33/04; C08L33/14; C08L63/00; C09D133/04; C09D133/06;
C09D133/14; C09J133/04; C09J133/14; (IPC1-7): C08F8/00
FIELD OF SEARCH: 525/337, 525/340, 525/341, 525/344, 525/351, 525/353, 525/355,
525/359.1, 525/385
US PATENT REFERENCES:
5132377 Heat-latent, cationic polymerization initiator and resin
compositions containing the same July, 1992 Nakano et al.
5070161 Heat-latent, cationic polymerization initiator and resin
compositions containing same December, 1991 Nakano et al.
5066722 Heat-latent curing catalyst and resin compositions containing
the same November, 1991 Nakano et al.
PRIMARY EXAMINER: Lipman, Bernard
Attorney, Agent or Firm:
Townsend, Donald E.
Parent Case Data:
CROSS REFERENCE TO A RELATED APPLICATION
This is a file wrapper continuation application of co-pending
application Ser. No. 07/791,507 filed Nov. 14, 1991, now abandoned.
CLAIMS:
What is claimed is:
1. A curable resin composition comprising:
(a) an acrylic polymer having a plurality of alicyclic epoxide
functions and a plurality of hydroxyl functions produced by
copolymerizing a monomer mixture comprising an acrylic monomer having
at least one alicyclic epoxide function and a hydroxyl group-containing
monomer;
(b) an amount of a polyfunctional alicyclic epoxide compound equal to
or less than the equivalent relative to the hydroxyl number of said
acrylic polymer; and
(c) an amount of heat-latent cationic polymerization initiator
effective to initiate a cationic polymerization reaction of said
acrylic polymer upon heating.
2. The cationic polymerizable resin composition of claim 1, wherein
said acrylic polymer has a mean molecular weight between about 3,000
and 10,000.
3. The curable resin composition of claim 1, wherein said monomer
mixture further contains an ethylenically unsaturated monomer free of
said alicyclic epoxide function and said hydroxyl group.
4. The cationic polymerizable resin composition of claim 3, wherein
said acrylic monomer having at least one alicyclic epoxide function is
an acrylate or methacrylate ester of an epoxide alicyclic alcohol, a
reaction product of a polyfunctional alicyclic epoxy compound with
acrylic or methacrylic acid, or an adduct of an epoxidized alicyclic
alcohol with an isocyanate of an acrylic monomer.
5. The curable resin composition of claim 1, wherein said hydroxyl
group-containing monomer is a hydroxylalkyl acrylate or methacrylate, a
reaction product of polycaprolactone with acrylic or methacrylic acid,
a reaction product of polymethylvalerolactone with acrylic or
methacrylic acid, a polyalkylene glycol monoacrylate or
monomethacrylate, 4-hydroxystyrene or N-(2-hydroxyethyl)-arylamide.
6. The curable resin composition as claimed in claim 1 further
comprising, as a chain extender, a polyol in such an amount that not
all alicyclic epoxide function of said acrylic polymer will be consumed
in the reaction with said polyol.
7. The curable resin composition as claimed in claim 1, wherein said
heat-latent cation polymerization initiator is an onium salt of
nitrogen, sulfur, phosphorus or iodine with a SbF[6]^--, BF[4]^--,
PF[6]^--, or CF[3] SO[3]^-- anion.
DESCRIPTION:
BACKGROUND OF THE INVENTION
This invention relates to a novel resinous composition containing an
acrylic polymer having a plurality of alicyclic epoxide functions. The
composition may be cured or crosslinked through the cationic
polymerization of the epoxide function and is useful as a resinous
component of coating compositions, sealants, potting or casting
compositions and the like.
Cationic polymerization of epoxy resins using a cationic polymerization
initiator is well-known. Usable initiators include Lewis acids,
Friedel-Crafts catalyst, boron trifluoride-ether complex,
photodegradable onium salts (S, Se, Te), diallyl iodonium salts and the
like. Initiators of this type are generally not selective with respect
to the reaction temperature. Therefore, an epoxy resin containing these
initiators begins to cure even at room temperature.
Japanese Patent Kokai (Laid Open) application Nos. 37003/83 and
37004/83 disclose another type of cationic polymerization initiator.
They are aliphatic or aromatic sulfonium salts capable of generating
carbonium cations upon heating to an elevated temperature. Initiators
of this type are known as "heat-latent cationic polymerization
initiator". U.S. patent application Ser. Nos. 07/356,903 and
07/532,716, both assigned to the assignee of this application, also
disclose a heat-latent cationic polymerization initiator. Epoxy resins
containing the heat-latent initiators are therefore normally
nonreactive but capable of curing at a temperature above the cleaving
temperature of the initiator. This provides a heat-curable,
one-component epoxy resin composition having a greater storage
stability and a longer pot life.
Epoxy resins or polymers used heretofore for this purpose are limited
to glycidyl ether or ester epoxy resins, typically bisphenol A epoxy
resins, and homo- and copolymers of glycidyl acrylate or methacrylate
(hereinafter collectively referred to as "(meth)acrylate").
We have now found that acrylic polymers having a plurality of alicyclic
epoxide functions are more sensitive to the cationic polymerization
than glycidyl epoxy resins in the presence of a heat-latent cationic
polymerization initiator. The present invention has its basis on this
finding.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a curable resin
composition comprising:
(a) an acrylic polyer having a plurality of alycyclic epoxide functions
and a mean molecular weight of greater than 1,000; and
(b) an amount effective to initiate the curing reaction of said acrylic
polymer of a heat-latent cation polymerization initiator.
The composition may contain a polyfunctional alicyclic epoxide compound
as a crosslinking agent and/or a polyol as a chain extender, and
various conventional additives such as solvents, pigments, UV
absorbers, and the like depending upon the end use of the composition.
The alicyclic epoxide functions possessed by the acrylic polymers used
in the present inventions are more sensitive to the cationic
polymerization reaction than glycidyl groups. Accordingly, the
composition of this invention may be cured at a baking temperature
lower than the temperature at which corresponding compositions
comprising glycidyl epoxy resins can be cured.
DETAILED DISCUSSION
Acrylic Polymers Having Alicyclic Epoxide Functions
Acrylic polymers having alicyclic epoxide functions may be prepared by
polymerizing or copolymerizing an acrylic monomer having an alicyclic
epoxide function. The term "alicyclic epoxide function" as used herein
refers to an epoxide bridge formed between two adjacent carbon atoms of
an alicyclic ring. Examples of these acrylic monomers may be classified
into the following three groups.
I. (Meth)acrylate esters such as:
3,4-epoxycyclohexylmethyl (meth)acrylate;
2-(1,2-epoxy-4,7-methano-perhydroinden-5(6)-yl)oxyethyl (meth)acrylate;
5,6-epoxy-4,7-methano-perhydroinden-2-yl (meth)acrylate:
1,2-epoxy-4,7-methano-perhydroinden-5-yl (meth)acrylate;
2,3-epoxycyclopentenylmethyl (methacrylate); and
3,4-epoxycyclohexylmethylated polycaprolactone (meth)acrylate of the
formula: ##STR1## wherein R^1 =H or CH[3] and n=1-10.
II. Adducts of (meth)acrylic acid with a polyfunctional alicyclic epoxy
compound such as:
3,4-epoxycyclohexyloxirane of the formula: ##STR2##
3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate of the
formula: ##STR3## 1,2,5,6-diepoxy-4,7-methano-perhydroindene of the
formula: ##STR4##
2-(3,4-epoxycyclohexyl)-3',4'-epoxy-1,3-dioxane-5-spirocyclohexane of
the formula: ##STR5## 1,2-ethylenedioxy-bis(3,4-epoxycyclohexylmethane)
of the formula: ##STR6## 1,3-dimethyl-2,3-epoxycyclohexyloxirane of the
formula: ##STR7## di-(2,3-epoxycyclopentyl)ether of the formula:
##STR8## 4',5'-epoxy-2'-methylcyclohexylmethyl
4,5-epoxy-2-methylcyclohexanecarboxylate of the formula: ##STR9##
bis-(3,4-epoxycyclohexylmethyl)adipate;
bis-(4,5-epoxy-2-methylcyclohexylmethyl) adipate; and
ethyleneglycol bis (3,4-epoxycyclohexanecarboxylate).
III. Adduts of alicyclic epoxide alcohols with (meth)acrylisocyanate or
isocyanotoethyl (meth)acrylate or
m-isopropenyl-α,α-dimethylbenzylisocyanate such as:
N-(3,4-epoxycyclohexyl)methylcarbonyl-(meth)acrylamide;
N-(5,6-epoxy-4,7-methano-perhydroinden-2-yl)oxycarbonyl-(meth)acrylamid
e; and
adducts of 3,4-epoxycyclohexylmethylated polycaprolactone with
(meth)acrylisocyanate of the formula: ##STR10## wherein R^1 =H or CH[3]
and n=1-10.
The above acrylic monomers may preferably be copolymerized with other
monomers free of the alicyclic epoxide function. Examples of such
comonomers include non-alicyclic epoxy group-containing monomers such
as glycidyl (meth)acrylate; hydroxyl group-containing monomers such as
2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate,
4-hydroxybutyl (meth)acrylate, 4-hydroxystyrene,
2-(2-hydroxyethoxy)ethyl (meth)acrylate, N-(2-hydroxyethyl)acrylamide,
reaction products of polycaprolactone with (meth)acrylic acid (PLACCEL
FA and PLAGCEL FM sold by Daicel Chemical Industries, Ltd.), reaction
products of polymethylvalerolactone with (meth)acrylic acid,
polyethyleneglycol mono(meth)acrylate, polypropyleneglycol
mono(meth)acrylate and polytetramethyleneglycol mono(meth)acrylate; and
other monomers such as styrene, α-methylstyrene, methyl (meth)acrylate,
ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl
(meth)acrylate, n-butyl (meth)acrylate, sec.-butyl (meth)acrylate,
t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl
(meth)acrylate stearyl (meth)acrylate, vinyl acetate, vinyl propionate
and the like.
The polymerization may be carried out by the solution polymerization
technique using a conventional radical polymerization initiator.
Examples of solvents used in the solution polymerization include
aliphatic hydrocarbons such as cyclohexane, dipentene and hexane;
aromatic hydrocarbons such as benzene, toluene, ethylbenzene and
aromatic petroleum naphtha; halogenated hydrocarbons such as
dichloromethane, dichloroethane, carbon tetrachloride, chlorform and
dichlorobenzene; nitrated hydrocarbons such as nitrobenzene,
nitromethane and nitroethane; ethers such as dioxane, tetrahydrofuran,
and dibutyl ether; glycol ethers such as ethyleneglycol monomethyl
ether, ethyleneglycol monoethyl ether, ethyleneglycol monobutyl ether,
ethyleneglycol monoethyl ether acetate, diethyleneglycol monomethyl
ether, diethyleneglycol monoethyl ether and diethyleneglycol monobuty
ether; ketones such as methyl ethyl ketone, ethyl isobutyl ketone,
cyclohexanone, acetone and isophorone; alcohols such as methanol,
ethanol, isopropanol, n-propanol, butanol, 2-ethylhexanol and
cyclohexanol; esters such as ethyl acetate and butyl acetate; and
mixtures of these solvents.
The resulting acrylic polymer should have a number average molecular
weight of greater than 1,000. The upper limit of molecular weight
generally lies at about 500,000. A molecular weight ranging between
about 3,000 and about 10,000 is preferable. If the molecular weight is
too low, the mechanical strength of the resulting cured products is not
satisfactory. Conversely, if the molecular weight is two high, the
polymer is too viscous resulting in decrease workability of
compositions containing the same.
Heat-Latent Cationic Polymerization Initiators
A variety of heat-latent cation polymerization initiators is known. For
example, initiators of sulfonium salt type have been disclosed in Endo
et al., J. Polym. Sci., Polym. Lett. Ed., 23, 359 (1985), Japanese
Patent Kokai Nos. 37003/83 and 37004/83. Other initiators of
benzylpyridinium salt, benzylammonium salt, and heterocyclic ammonium
salt-types have been disclosed in Sang-Bong Lee et al., Polym. Prep.
Jpn., 38, 271 (1989) and U.S. patent application Ser. Nos. 07/356,903
and 07/532,716, both assigned to the assignee of this application. The
disclosures of these references are incorporated herein by reference.
Phosphonium salt- and iodonium salt-type heat-latent initiators are
also known. Any of these known heat-latent initiators may be used in
the present invention. Generally speaking, the heat-latent initiators
are onium salts of nitrogen, sulfur, phosphorus and iodine with a
SbF[6]^--, BF[4]^--, AsF[6]^--, PF[6]^-- or CF[3] SO[3]^-- anion.
Specific examples thereof include:
N,N-diemethyl-N-benzylanilinium hexafluoroantimonate,
N,N-diethyl-N-benzylanilinium tetrafluoroborate,
N-(2,3-dimethylbenzyl)pyridinium hexafluoroantimonate,
N-(2,3-dimethylbenzyl)pyridinium hexafluoroantimonate,
N-(2,3-diethylbenzyl)pyridinium trifluoromethane-sulfonate,
N,N-dimethyl-N-(4-methoxybenzyl)anilinium hexafluoroantimonate,
N,N-diethyl-N-(4-methoxybenzyl)anilinium hexafluoroantimonate,
N,N-diethyl-N-(4-methoxybenzyl)-N-p-tolylammonium hexafluoroantimonate,
N,N-dimethyl-N-(4-methoxybenzyl)-N-p-tolylammonium
hexafluoroantimonate,
triphenylsulfonium tetrafluoroborate,
triphenylsulfonium hexafluoroantimonate,
triphenylsulfonium hexafluoroarsenate,
ADEKA CP-66 (Asahi Denka Kogyo K.K.),
ADEKA CP-77 (Asahi Denka Kogyo K.K.),
tri-(4-methoxyphenyl)sulfonium hexafluoroarsenate,
diphenyl-(4-phenylthiophenyl)sulfonium hexafluoroantimonate,
ethyltriphenylphosphonium hexafluoroantimonate,
tetrabutylphosphonium hexafluoroantimonate,
diphenyliodonium hexafluoroarsenate,
di-4-chlorophenyliodonium hexafluoroarsenate,
di-4-bromophenyliodonium hexafluoroarsenate,
di-p-tolyliodonium hexafluoroarsenate, and
phenyl-(4-methoxyphenyl)iodonium hexafluoroarsenate.
Heat-Curable Resin Compositions
The heat curable resin composition of this invention contains an amount
of a heat-latent cation polymerization initiator effective to initiate
the polymerization reaction upon heating of the alicyclic epoxy acrylic
polymers. This amount varies with particular initiators and polymers
used but generally ranges from about 0.1 to 10%, preferably from 0.3 to
5% by weight relative to the nonvolatile content of the acrylic
polymer. Excessive use of the initiator should be avoided since it may
adversely affect the properties of the resulting cured products such as
water resistance, color and the like. Excessive addition of heat-latent
initiators may also have an adverse affect on the storage stability of
the composition.
When the alicyclic epoxy acrylic polymer has a plurality of hydroxyl
groups, the composition of this invention may comprise a polyfuctional
alicyclic epoxide compound as used in the preparation of group II of
acrylic monomers having an alicyclic epoxide function as a crosslinking
agent which serves as a reactive diluent as well. The amount of such
polyfunctional alicyclic epoxide compounds should be, when used, equal
or less than the equivalent relative to the hydroxyl number of the
acrylic polymer.
The composition of this invention may also comprise, as a chain
extender, a low molecular weight-polyol such as ethylene glycol,
diethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol,
pentaerythritol and trimethylolpropane, or a high molecular
weight-polyol such as polyether polyols, polyester polyols and
polycaprolactone polyols. The amount of such polyols should be, of
course, such that not all alicyclic epoxide functions of the acrylic
polymer will be consumed in the reaction with the chain extender.
The composition of the present invention may contain a variety of
conventional additives depending upon its end use. For example, the
composition for coating purposes may contain a conventional solvent,
pigment, UV absorber such as 2-(2'-hydroxyphenyl)benzotriazole or its
derivative or 2-hydroxybenzophenone, surface conditioner and the like.
The following examples are intended to further illustrate the present
invention without limiting thereto. All parts and percents therein are
by weight unless otherwise indicated.
PRODUCTION EXAMPLE 1
3,4-Epoxycyclohexylmethyl methacrylate
Step A
A 4 liter, 4 necked flask equipped with a Vigreaux column, thermometer,
nitrogen gas tube and vacuum sealer was charged with 1802 g of methyl
methacrylate, 841.3 g of cyclohexen-4-ylmethanol, 52.8 g of
hydroquinone and 26.4 g of p-toluenesulfonic acid. The reactants were
stirred while blowing nitrogen gas at a bath temperature of 100° C.
until a distillate began to flow out from the column. Then the bath
temperature was raised gradually while maintaining the top temperature
of the column below 70° C. The reaction was continued for additional 6
hours and then stopped when the bath temperature was 120° C. 605 g of
the distillate was collected. Then the reaction mixture was distilled
under vacuum to remove unreacted methyl methacrylate and the resulting
cyclohexen-4-ylmethyl methacrylate was purified by fractional
distillatin under reduced pressure.
Yield, 1279 g (94.6% of theory), b.p. 67° C./0.2 mmHg.
Step B
A 8 liter, 4 necked flask equipped with a thermometer, cooling jacket,
stirring means and drip funnel was charged with 200 g of
cyclohexen-4-ylmethyl methacrylate produced in Step A and 1200 ml of
methylene chloride. The reactants were cooled to a temperature below
10° C. A solution of 268.6 g of m-chloroperbenzoic acid (80% purity,
Kishida Chemicals) in 2800 ml of methylene chloride was added thereto
dropwise over 3 hours and then allowed to react for additional 3 hours
with stirring. After the reaction, an amount of 10% aqueous solution of
sodium sulfite was added to the reaction mixture and allowed to react
at room temperature for 1 hour to decompose unreacted perbenzoate.
After having confirmed the absence of perbenzoate using starch-iodine
indicator paper, the reaction mixture was washed with 1000 ml of an
aqueous solution containing 81 g of sodium carbonate and then with an
amount of saline successively. Thereafter the mixture was dried over
magnesium sulfate and evaporated under reduced pressure with addition
of 40 mg of p-methoxyquinone as a polymerization inhibitor to remove
the solvent. 206 g of crude product of the titled compound was
obtained. Yield: 95% of theory.
^1 H-NMR (in CDCl[3], TMS standard, ppm), 1.4-2.4 (m, 7H); 3.15, 3.19
(m, 2H); 3.92, 3.96 (d, 2H); 5.55(s, 1H); 6.09 (s, 1H)
PRODUCTION EXAMPLE 2
5,6-Epoxy-4,7-Methano-Perhydroinden-2-yl Methacrylate
A 3 liter, 4 necked flask equipped with a thermometer, cooling jacket,
stirring means and drip funnel was charged with 166 g of
5,6-epoxy-2-hydroxy-4,7-methanoperhydroindene (CELOXIDE 4000, Daicel
Chemical Industries, Ltd.), 87.01 g of pyridine and 1000 ml of benzene.
To this was added a mixture of 104, 54 g of methacryloyl chloride and
100 ml of benzene dropwise over 2 hours while keeping the inner
temperature at 10° C. After the addition the reaction mixture was
stirred for 3 hours at room temperature. After having confirmed the
absence of the acid chloride by IR spectrometrically, the reaction
mixture was filtered to remove solids washed with an amount of 5%
aqueous solution of sodium carbonate, dried over magnesium sulfate, and
evaporated under reduced pressure with addition of 40 mg of
p-methoxyquinone to remove the solvent. 199 g (85% of theory) of a
crude product of the title compound was obtained.
Structural formula: ##STR11##
PRODUCTION EXAMPLE 3
2-(1,2-Epoxy-4,7-Methano-Perhydroinden-5(6)-yl)oxymethyl methacrylate
A 3 liter, 4 necked flask equipped with a thermometer, cooling jacket,
stirring means and drip funnel was charged with 555 ml of methylene
chloride and 95.7 g of
2-(4,7-methano-3a,4,5,6,7,7a-hexahydroinden-5(6)-yl)oxyethyl
methacrylate (QM 657, Rohm and Haas) of the formula: ##STR12##
To this was added dropwise a solution of 87 g of m-chloroperbenzoic
acid (80% purity, Kishida Chemical) in 888 ml of methylene chloride
over 1 hour while keeping the inner temperature at 10° C. and then
allowed to react for additional 3 hours with stirring. After the
reaction, an amount of aqueous solution of sodium sulfite was added to
the reaction mixture and allowed to react at room temperature for 1
hour with stirring to decompose unreacted perbenzoate. After having
confirmed the absence of perbenzoate using starch-iodine indicater
paper, the reaction mixture was washed with a 5% aqueous solution of
sodium carbonate and saline successively, dried over magnesium sulfate,
and then evaporated under reduced pressure to remove the solvent. 103.8
g of the title compound was obtained almost in a quantitative yield.
Structural formula: ##STR13##
PRODUCTION EXAMPLES 4-10
Acrylic Polymers Having Alicyclic Epoxide Functions
450 g of xylene placed in a 2 liter, 4 necked flask equipped with a
thermometer, drip funnel and stirring means was heated to 130° C. To
this was added dropwise Mixture #1 shown in Table 1 below over 3 hours.
Thereafter the mixture was stirred for 30 minutes at 130° C. Then
Mixture #2 shown in Table 1 was added dropwise over 30 minutes and
stirring was continued for additional 1.5 hours at 130° C. After
cooling, a viscous, colorless and transparent solution of an acrylic
polymer, was obtained. The nonvolatile content of the solution and the
number average molecular weight of the polymer are also given in Table
1.
TABLE 1
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___
PRODUCTION EXAMPLE 4 5 6 7 8 9 10
_______________________________________________________________________
___
Mixture #1, parts
Monomer of Production
500 500
Ex. 1
Monomer of Production 580
Ex. 2
Monomer of Production 670
Ex. 3
GMA^1) 500 500
HEMA^2) 93 93 50 50 273
ST^3) 167 167
NBA^4) 240 240 220 180 341
2 EHA^5) 120 120
MMA^6) 380 380 150 100 380
Xylene 450 450 450 450 912 912 912
Initiator^7)
100 100 100 100 50 50 50
Mixture #2
Xylene 88 88 88 88 88 88 88
Initiator^7)
5 5 5 5 3 3 3
Properties
Mn 3200
3100
3300
3500
8500
8200
8300
Nonvolatile, %
65 65 65 65
50 50 50
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___
Remarks: ^1) Glycidyl methacrylate ^2) 2Hydroxyethyl methacrylate ^3)
Styrene ^4) nButyl acrylate ^5) 2Ethylhexyl acrylate ^6) Methyl
methacrylate ^7) tButyl peroctate
EXAMPLES 1-3 AND COMPARATIVE EXAMPLES 1-2
Various coating compositions were formulated using varnishes and other
components as shown in Table 2 below. The heat-latent initiator used
was N-(4-methoxybenzyl)-N,N-dimethylanilinium hexafluoroantimonate. The
compositions were each applied on a tinplate with a bar coater at a dry
film thickness of 20 microns, and backed at 110° C. for 30 minutes. The
resulting cured films were evaluated for solvent resistance and
smoothness. The results are also shown in Table 2.
TABLE 2
______________________________________
COM. EXAMPLES EXAMPLES 1 2 3 1 2
______________________________________
Components, parts
Varnish of Pro. Ex. 6
100 80 80
Varnish of Pro. Ex. 7 100
Varnish of Pro. Ex. 10
20
CELOXIDE 2021^8) 20 100
Heat latent initiator
1 1 1 1 1
Evaluation
Solvent resistance^9)
Good Good Good Good Not
good
Smoothness^10)
Good Good Good Not Good
good
______________________________________
Remarks: ^8) Alicyclic epoxide compound sold by Daicel Chemical
Industries, Ltd. ^9) Rubbing test with xyleneimpregnated fabric at 20
reciprocations. Good: No change. Not Good: Dissolved or peeled off.
^10) Visual judgement. Good: Continuously flat surface with high gloss.
Not Good: Uneven surface or no gloss.
EXAMPLES 4-6 AND COMPARATIVE EXAMPLE 3
Various coating compositions were formulate using varnishes and other
components as shown in Table 3 below. The heat-latent initiator used
was a sulfonium compound ADEKA CP-77 (Asahi Denka Kogyo K.K.). The
compositions were each applied on a tinplate with a bar coater at a dry
film thickness of 20 microns, and baked at 110° C. for 30 minutes. The
resulting cured films were evaluated for solvent resistance and
smoothness. The results are also shown in Table 3.
TABLE 3
______________________________________
COM. EXAMPLES EXAMPLES 4 5 6 3
______________________________________
Components, parts
Varnish of Pro. Ex. 4
100
Varnish of Pro. Ex. 5
100
Varnish of Pro. Ex. 7 100
Varnish of Pro. Ex. 9 100
Heat latentinitiator
1 1 1 1
Evaluation
Solvent resistance
Good Good Good Not good
Smoothness Good Good Good Good
______________________________________